It is well known that two processes consisting of a photographing exposure process for forming latent images and a development process for converting the formed latent images into silver images or dye images are necessary in obtaining images by a silver halide photographic process (for example, refer to Mees and James, The Theory of the Photographic Process). The formation of latent images by photographic exposure is chemically caused by a very slight change of silver halide crystals, and latent images themselves are essentially unstable. Accordingly, the latent images have a propensity to easily decay over the passage of time from photographic exposure to development processing, which characteristic is known as the fading of latent images. The progress of the fading of the latent images generally depends upon the preservation condition of the exposed photographic materials. For example, it has been observed that the degree of fading is remarkably high when such materials are preserved at a high temperature, and is low when such are preserved at a low temperature.
The simplest process for avoiding the disadvantages due to the fading of latent images is obviously one which comprises carrying out development just after photographic exposure; and the second simplest process is one in which the photographic sensitive materials are preserved by cooling at a low temperature for the period from exposure to development. These processes are easy solutions from the chemical viewpoint, but it is hard to say that they are the preferred solutions, considering the users convenience. Noting the practical conditions of use and the practical state of such use, in the case of negative materials and reversal materials for photography, they are often allowed to stand at room temperature for several months from exposure to development. In the case of positive materials for copying, these are also allowed to sometimes stand for several months.
From the above-described reason, it is desired to obtain silver halide photographic light-sensitive materials in which the fading of latent images is prevented, and various methods have been attempted hitherto. However, as a result of our studies, it has been found that all of these known processes, namely, the process using hydroxyl group substituted aromatic compounds as described in German Pat. No. 1,107,508, the process using 1,3-diones as described in U.S. Pat. No. 3,447,926, the process using nitrilotriacetic acid as described in U.S. Pat. No. 3,318,702, the process described in U.S. Pat. No. 3,424,583 and the process described in German Pat. No. 1,173,339, are insufficient for the abovedescribed purpose.